Radiographic plate changer



M. MORRISON RADIOGRAPHI C PLATE CHANGER Y Jan. 7, 1936.

Filed April 4, 1931 INVENTOR ATTORNEY Patented Jan. 7, 1936 UNITEDSTATES PATENT FFICE RBIOGRAPHC PLATE CHANGER ration of DelawareAppiication April 4, i931, Serial No. 527,659

11 Claims.

My invention relates to plate' changers for radiographic apparatus andare sometimes referred to in the art as serialographs. Devices of thisgeneral character are well known in the art for exposing a plurality ofsensitized films to X- radiation emanating from an X-ray tube and adevice of this character is usually employed in taking stereoscopicradiographic pictures of an object in which the angle between the X-raytube and the plate changer is changed with the exposure of each film.This latter is usually accomplished by changing the angle of the platechanger or the angle of the X-ray tube relative to the object to beradiographed.

Heretofore the operation of the plate changers have been dependent upongravity, electric motor or fluid actuated mechanism. These devices arereadily susceptible to Wear and break down and on the whole areunreliable and cumbersome.

It is, therefore, an object of my invention to provide a plate changerwhich is entirely automatically actuated by a mechanical device which isnot readily susceptible to wear or break down.

Another object of my invention is to provide a plate changer in whicheach of the individual films assumes a position adjacent a portion ofthe apparatus which is pervious to X-rays for exposure of each lm,

Still further objects of my invention will become apparent to thoseskilled in the art by reference to the accompanying drawing wherein Fig.1 is a rear plan view of my device; and

Fig. 2 is a sectional View taken on line lI-II of Fig. 1 with a portionof the apparatus broken away to better illustrate the mechanism.

Referring now to the drawing in detail I have shown a frame member 2which is provided with a pair of. laterally extending lugs 3 and 4 ateach end of the frame member. A pair of square tracks and 6 forming aguideway extend longitudinally of the frame member and are secured tothese lateral lugs 3 3 and @-4 respectively. The track member 5 ishollow for a purpose more fully hereinafter explained.

A cassette tray i, provided with a pair of large rollers 8 and aplurality of pairs of smaller laterally disposed rollers S, is arrangedto move longitudinally of the frame member by the rollers being inengagement with the pair of tracks 5 and S respectively. The cassettetray l is provided with a pair of. laterally extending lugs II and acoil spring I2 is secured to one of these lugs and to a bracket memberI3. A similar coil spring i4 is secured to the other lug II and to asimilar bracket member I5 disposed at the opposite end of the framemember 2.

A square shaft I6 is disposed internally of the hollow track 5 and isarranged to be moved longitudinally of this track member by means of a 5control handle I'I to be more fully hereinafter described. The bracketmembers I3 and I5 are secured to the square shaft I6 and the coilsprings l2 and I4 are likewise secured to these bracket members asbefore stated. The coil springs are, 10 however, secured to thesebracket members by means of a set screw and lock nut arrangement in awell known manner for increasing or decreasing the tension of these coilsprings.

The handle for control lever II is pivotally secured to a bracket memberIB which is in turn rigidly secured to one of the surfaces of the trackmember 5.

A pin I9 is rigidly secured to the square shaft I B and extends throughan elongated slot pro- 20 vided in the track member 5 and is pivotallysecured to the handle of control lever I'I. The control lever I'I isprovided with a pair of pivoted auxiliary handles 22 which engage a pairof pins 23 slidably mounted in bearings 23 and these 25 handles 22 arebiased away from the lever I'I by means of a pair of coil springs 24.The bracket member I8 is provided with notches 25 which are engaged bythe respective pins 23 as the control lever is rotated about its pivot.

The cassette tray 'I is provided on its rear surface with a pair ofbeveled stop plates 26, and a solenoid 2l having a spring pressedplunger 28 is arranged to engage the plates 26, and thus forms a detentto maintain the cassette tray at the respective limits of its travel,with the sensitized films carried by the cassette tray in alignment witha section of the frame member pervious to X-rays.

The frame member is provided with a cover 29 40 which supports a bracket30 to which the solenoid 2l is secured and a similar cover 32 is securedto the front of the frame member and is provided with a section thereofpervious to X- rays and the remainder thereof opaque to X- rays. Thesections of this cover opaque to X- rays are provided with suitablehinged doors 3l and 3 I for loading and unloading the films from thecassette tray.

The cassette tray is provided with a pair of pins 33 and 33 which arepositioned to engage a pair of contact members 34 and 35 respectively,disposed at each end of the frame member 2.

A manually operable switch 35 is provided, which in actual practice, isusually mounted upon the control lever I1. This switch 36 is providedwith a contact segment positioned to engage a plurality of contactterminals 31, 38 and 39 respectively. A conductor 40 extends from one ofthe contact members 35 to the contact terminal 31 and a similarconductor 42 extends from the contact member 34 to the contact terminal39. A conductor 43 extends from the contact terminal 38 to a push buttonswitch 44 and from this latter switch to a suitable attachment plug 45.A conductor 46 extends from the attachment plug 45 to the solenoid 21while a conductor 41 interconnects the remaining contact members 34 and35.

The operation of my device may be best understood by assuming a givenoperation. Assuming, therefore, it is desired to expose a series ofsensitized films to the X-rays radiating from an X-ray tube the cassettetray 1 is initially moved to one of its extremities of travellongitudinally of the frame member 2, such as for example, to theposition shown in dotted lines to the right of Fig. 1. One of thesections of the cover 32, which is provided with a door, is open and asensitized film placed in the cassette tray.

The attachment plug 45 is connected to a suitable source of electricalenergy and the switch 36 is moved to the position shown by the arrowestablishing contact between the contact terminais 31 and 38. Thecontact terminals 35 are closed by the pin 33' when the cassette tray isin this position.

The push button switch 44 is then pressed to energize the solenoid 21thus causing retraction of the spring pressed plunger 28 whichdisengages one of the stop plates 26 and allows the spring I4 which willbe expanded with the cassette tray in the assumed position, to move thesame longitudinally of the frame member to the left as shown in fulllines in the figure. That section of the plate 32, which is alsoprovided with a door opaque to X-rays, is then opened and a filminserted in this section of the cassette tray. The cassette tray beingloaded with unexposed Illms is now ready for the taking of aradiographic picture. With the cassette tray in the position lastmentioned, namely, to the left as shown in full lines in Fig. 1, theright hand section of the cassette tray 1 will be in alignment with thesection of the cover 32, of the frame member 2, which is pervious toX-rays with the left hand section of the cassette tray disposed in backof one of the sections opaque to X-rays. l

The pin 33 of the cassette tray 1 will be in engagement with one of thepairs of the contact members 34 which will cause the closing of thesecontact members. The switch 36 is moved in the direction as shown inFig. 1 which establishes connection between the contact terminals 38 and39 and the contact members 35 will now be open. With the cassette trayin the position shown, namely to the left as shown in full lines in thefigure, the coil spring I2 will be expanded and the coil spring I4 willbe contracted.

As these two coil springs are of substantially the same tensile strengthupon release of the cassette tray and its movement in response to thepotential energy of the coil spring I2 a condition would occur where thepotential energy of the respective springs I2 and I4 would tend toequalize each other, which condition would occur before the cassettetray 1 has moved sufficiently to the right, as shown in dotted lines inFigure l,

for one of the plates 26 to be engaged by the plunger 28 of the solenoid21.

In order to increase the potential energy of the expanded spring Iprovide the control lever I1. This lever is provided with a pin I9engaging the square shaft I6 and upon movement of the lever the squareshaft I6 is moved internally of the track member 5. The bracket membersI3 and I5 being secured to the respective springs I2 and I4 and to eachend of the square shaft I6 causes further expansion of the coil springI2 as the square shaft I6 is moved to the right, This further expansionof the coil spring increases the potential energy of the spring to anamount sufficient to overcome the potential energy of the spring I4 asthe same tends to become effective during movement of the cassette tray,and allows the latter to move the additional required amount to permitthe plunger of the solenoid to engage the stop plate 26 and maintain thecassette tray in its other extremity of travel.

Upon closing of the switch 44 the circuit will be completed to thesolenoid 21, which extends from one side of the plug 45 throughconductor 46, solenoid 21, conductor 41 through the contact members 34,conductor 42 to the contact terminal 39, through the switch 36 to theterminal 38, thence by means of conductor 43 through the switch 44 backto the other side of the plug 45, This allows the solenoid 21 to retractthe plunger 28 and disengage the stop plate 26.

The coil spring I2 will then cause movement of the cassette tray 1 tothe right, which due to the increased potential energy given the springI2 by the control handle I1 will enable the spring pressed plunger 28 toengage the other plate 26 and maintain the cassette tray in a positionshown in dotted lines.

As the cassette tray moves to this position the pin 33' will immediatelycause the closing of the contact members 35, which would immediatelycause the solenoid to become energized, should the operator still havethe switch 44 closed,.were it not for the fact that the switch 36 hasthe circuit to the solenoid open, as well as the fact, that the pin 33has opened the contact members 34 in moving to the right.

When it is desired to again have the cassette tray move to the left asshown in full lines, the switch 36 must be moved to the position shownby the arrow to establish a contact between the terminals 31 and 38 topartially complete the circuit to the solenoid. The control lever I1must likewise be moved to the position as shown, as indicated by thearrow to move the square shaft I6 to the left and increase the potentialenergy of the spring I4 which would now be expanded. Immediately uponclosure of the circuit by the operator actuating the switch 44 thecassette tray will be again released by the solenoid 21 and it will movefrom the position indicated in dotted lines to that shown in full lines.

It can thus be seen that once the cassette tray is moved to either ofits positions and either of the respective springs I2 and I4 initiallytensioned the operation of the device is entirely automatic.

Upon movement of the tray to one position, one of the springs becomestensioned, while the other is contracted and upon movement of thecassette tray to the opposite position the inverse condition of thesprings results. This enables each of the springs to alternately act asshock absorbers for the cassette tray while at the same time permittingthe potential energy of the tensioned spring to move the tray to itslimits of travel.

It is, therefore, obvious that the mechanism utilized for actuating thedevice is susceptible to very little Wear, is simple in construction andpositive in its operation.

Although I have shown one specic embodiment of my invention I do notdesire to be limited thereto as various other modications of the samemay be made Without departing from the spirit and scope of the appendedclaims.

What is claimed is:

1. In an automatic plate changer for X-ray photography the combinationof a guideway, a cassette tray movable longitudinally along saidguideway, tensioning means connected at one end with said cassette tray,a vportion of said tensioning means serving to move the tray in onedirection and the remaining portion thereof serving to move the tray inan opposite direction, means connected with the other end of saidtensioning means for increasing the tension of either of said portionsthereof, and releasable means cooperating with said cassette tray forholding the same stationary at predetermined points in its path ofmovement.

2. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable substantially the entire length thereofalong said guideway, tensioning means connected to said cassette trayand operable to cause movement of the latter along said guideway in onedirection, tensioning means connected to said cassette tray and operableto cause movement of the latter along said guideway in an oppositedirection, said tensioning means being connected to said cassette trayin opposition with respect to each other, means connected with both ofsaid tensioning means ,and operable to increase the potential energy ofeither of said tensioning means suiciently to cause said tensioningmeans having increased potential energy to cause movement of saidcassette tray substantially the entire length of said frame memberagainst the potential energy of said opposed tensioning means as thelatter becomes effective during movement vof said cassette traylongitudinally of said frame member, and releasable means carried bysaid frame member and engageable with said cassette tray to maintain thelatter at its extremities of travel against the potential energy ofeither of said tensioning means.

3. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable substantially the entire length thereofalong said guideway, tensioning means connected to said cassette trayand operable to cause movement of the latter along said guideway in onedirection, tensioning means connected to said cassette tray and operableto cause movement of the latter along said guideway in an oppositedirection, said tensioning means being connected to said cassette trayin opposition with respect to each other, a detent carried by said framemember and engageable with said cassette tray for maintaining the latterat either oi its extremities of travel, means connected with both ofsaid tensioning means and operable to increase the potential energy or"either of said tensioning means suiciently to cause said tensioningmeans having increased potential energy to move said cassette tray to anengaging position with said detent against the potential energy of saidopposed tensioning means as the latter becomes effective during movementof said cassette tray longitudinally of said frame, and means carried bysaid frame member and responsive to actuation by an operator forreleasing said detent and causing said tensioning means having increasedpotential energy to move said cassette tray.

4. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a portion pervious to X-rays and theremainder thereof opaque to X-rays, a guideway in said frame member andextending longitudinally thereof, a cassette tray for encasing aplurality of sensitized films disposed in said frame member and arrangedto be automatically moved along said guideway longitudinally of saidframe member, spring tensioning means connected to said cassette trayand operable to cause movement of the latter Within said frame alongsaid guideway in one direction of travel, spring tensioning meansconnected to said cassette tray and operable to cause movement of thelatter within said frame along said guideway in an opposite direction oftravel, a detent carried by said frame member and engageable with saidcassette tray to maintain the latter in various positions during itsmovement to cause at least one of said iilms to be always in a positionrelative to the portion of said frame member pervious to X-rays,manually operable means connected to both of said spring tensioningmeans and operable to increase the tension of either of said springtensioning means, and electrically operated means carried by said framemember and operable to release said detent and render said springtensioning means having increased tension eiective to move said cassettetray longitudinally of said frame member along said guideway.

5. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cover for said framemember provided with a portion pervious to X- rays and the remainderthereof opaque to X-rays, a cassette tray for encasing a plurality ofsensitized lms disposed in said frame member and movable longitudinallythereof along said guide- Way, a pair of coil springs of substantiallyequal potential energy connected to said cassette tray, one of said coilsprings being effective to cause movement of said cassette tray in onedirection and the other of said springs being effective to causemovement of said cassette tray in the other direction, a detent carriedby said frame member and engageable with said cassette tray to maintainthe latter at either of its extremities of travel against the tension ofone or the other or" said springs, manually operable means connected toboth of said coil springs to increase the potential energy of the springunder tension when said cassette tray is at one extremity of travel, andelectrically operated means carried by said frame member to cause saiddetent to disengage said cassette tray and cause thespring under tensionto move said cassette tray longitudinally of said frame member alongsaid guideway.

6. In an automatic plate changer for X-ray photography the combinationof a frame member provided With a guideway, ,a cassette tray carried bysaid frame member and movable longitudinally thereof substantialy theentire length of said guideway, a coil spring connected to said cassettetray and operable to move the latter in one direction along saidguideway, a coil spring connected to said cassette tray and operable tomove the latter along said guideway in an opposite direction, mechanismconnected to both of said coil springs. provided with an actuatingleverand operable to increase the potential energy of each of said coilsprings as the respective springs are tensioned by movement of saidcassette tray, a solenoid carried by saidi frame member and providedwith a plunger engageable with said cassette tray to maintain the latterin a xed position relative to said frame member, and manually operablemeans electrically connected to said solenoid to cause disengagement ofthe plunger relative to said cassette tray to render the respectivespring under tension effective to move said cassette tray along saidguideway longitudinally of said frame member.

'7. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable 1ongitudinally of the latter substantiallythe entire length of said guideway, a coil spring connected to saidcassette tray and operable to move the latter in one direction alongsaid guideway, a coil spring connected to said cassette tray andoperable to move the latter along said guideway in an oppositedirection, said coil springs being secured atone of their respectiveends to said cassette tray and opposed relative to each other, mechanismconnected to both of said coil springs provided with a manually operablelever and operable to increase the potential energy of each of saidsprings after the respective spring has been tensioned by movement ofsaid cassette tray to cause said tensioned spring to move said cassettetray in an opposite direction against the potential energy of saidopposed coil spring, and a detent carried by said frame member andengageable with said cassette tray and operable by a solenoid associatedtherewith to release said cassette tray and cause said tensionedcoil'spring to move said cassette tray and tension the opposed coilspring preparatory to further movement of said cassette tray in adirection opposite to said rst mentioned direction.

8. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable longitudinally thereof along saidguideway, tensioning means connected to said cassette tray and operableto cause movement thereof, a detent carried by said frame member andengageable with said cassette tray to maintain the latter at oppositelimits of its longitudinal movement, electrically operated meansassociated with said detent for causing the release of the latterrelative to said cassette tray, an electrical circuit including saidelectrically operated means, a switch, and a pair of contact membersAdisposed at one end of said frame member, said contact members beingactuable by movement of said cassette tray to open and close thiscircuit, a second electrical circuit including said electricallyoperated means, said switch, and a pair of contact members disposed atthe opposite end of said frame member, said last mentioned contactmembers being actuable by movement of said cassette tray` for openingand closing this second circuit, and an auxiliary switch common to bothof said circuits and operable to interrupt one of said circuits at atime to prevent the movement of said cassette tray from completing thecircuit to said electrically operated means by closure of the contactmembers included in the circuit interrupted by said auxiliary switch,and again releasing Ysaid detent after said cassette tray has moved toone of its limits of travel, except by l5 operation of said iirstmentioned switch.

9. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable longitudinally of the latter substantiallythe entire length of said guideway, tensioning means connected to saidcassette tray and operable to move the latter in one direction alongsaid guideway, tensioning means connected to said cassette tray andoperable to move the latter along said guideway in an oppositedirection, said tensioning means being connected to said cassette trayin opposition relative to each other, a detent carried by said framemember and engageable with said cassette tray to maintain the latter atopposite limits of its longitudinal movement, means connected with bothof said tensioning means and operable to increase the potential energyof either of said tensioning means sufficiently to cause said tensioningmeans having increased potential energy to move said cassette tray to anengaging position with said detent against the potential energy of saidopposed tensioning means as the latter becomes effective during movementof said cassette tray, electrically operated means carried by said framemember for releasing the engagement of said detent relativel to saidcassette tray, an electrical circuit including said electricallyoperated means, a switch, and a pair of contact members disposed at oneend of said frame member, said contact members being actuable bymovement of said cassette tray for opening and closing this circuit, asecond electrical circuit including said electrically operated means,said switch, and a pair of contact members disposed at the other end ofsaid frame member and actuable by movement of said cassette tray foropening and closing this second circuit, and an auxiliary switch commonto both of said circuits and operable to interrupt one o1' said circuitsat a time to prevent movement of said cassette tray from completing thecircuit to said electrically operated means, by closure of the contactmembers included in the circuit interrupted by said auxiliary switch,and again releasing said detent after said cassette tray has moved toone of its limits of travel, except by operation of said first mentionedswitch.

10. In an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable longitudinally of the latter substantiallythe entire length of said guideway, tensioning means connected to saidcassette tray and operable to move the latter in one direction alongsaid guideway, tensioning means connected to said cassette tray andoperable to move the latter along said guideway in an oppositedirection, mechanism connected to both of said tensioning means providedwith a manually operable lever and operable to increase the tension ofeither of said tensioning means, electrically operated means carried bysaid frame member, and means engageable with said cassette tray andoperable by said electrically operated means to render one of saidtensioning means effective to move said cassette tray along saidguideway longitudinally of said frame member.

il. n an automatic plate changer for X-ray photography the combinationof a frame member provided with a guideway, a cassette tray carried bysaid frame member and movable longitudinally thereof along saidguideway, a tensioning member connected toy said cassette tray formoving the latter along the guideway of said frame member in onedirection, a tensioning member connected to said cassette tray formoving the latter along the guideway of said frame member in an oppositedirection, means connected with both of said tensioning members andoperable to increase the tension of one of said tensioning members at atime, electrically operated means carried by said frame member, andmeans engageable with said cassette tray for holding the latter at itsextremities of travel against the tension of either of said tensioningmembers and operable by said electrically operated means in response toactuation by an operator to release said cassette tray thus causing saidtensioning member having increased tension 10 to become eective and movesaid cassette tray.

MONTFORD MORRISON.

